Commander Takeshi Rolland Hartmann served aboard the UNSC Phoenix during the Covenant invasion of Earth. He was the first to alert UNSC forces of the Forerunner dreadnought as it entered realspace in orbit.

Trivia

"Takeshi" (武) can mean "military man." "Rolland" is a variation of "Roland", a French character depicted as the chief paladin of Charlemagne. "Hartmann" means "brave man", derived from the Germanic element hard "brave, hardy" combined with man.